Q:

# A journal article reports that a sample of size 5 was used as a basis for calculating a 95% CI for the true average natural frequency (Hz) of delaminated beams of a certain type. The resulting interval was (230.061, 233.807). You decide that a confidence level of 99% is more appropriate than the 95% level used. What are the limits of the 99% interval?

Accepted Solution

A:
Answer:(229.5450, 234. 3230)Step-by-step explanation:Given that a  journal article reports that a sample of size 5 was used as a basis for calculating a 95% CI for the true average natural frequency (Hz) of delaminated beams of a certain type.95% confidence interval was$$(230.061, 233.807)\\$$From confidence interval we find mean as the average of lower and upper bound.Mean = $$\frac{463.868}{2} \\=231.934$$Margin of error = upper bound -mean=$$1.873$$i.e. 1.96 * std error = 1.873For 99% interval margin of error would be 2.58*std errorso margin of error for 99% = $$2.58*\frac{1.873}{1.96} \\=2.3890$$Confidence interval 99% lower bound = Mean - 2.3890 =229.5450Upper bound = Mean +2.3890 = 234.3230